Spring-toggle mechanism for tool elements or the like



May 10, 1960 T. A. OLEARY 2,936,011

SPRING-TOGGLE MECHANISM FOR TOOL ELEMENTS OR THE LIKE Filed May 28, 1957 2 Sheets-Sheet 1 mllllllllllllllllilillqelllfl INVENTOB 77/5000? 4 0/549) May 10, 1960 T. A. OLEARY 2,936,011 .SPRING-TOGGLE MECHANISM FOR TOOL ELEMENTS OR THE LIKE Filed May 28, 1957 Fig.7.

2 Sheets-Sheet 2 E INVENTOR. 72 5000? 44. 0 la/w) Q BY 22 $2M 25M;

477'0/P/VEY SPRING-IOGGLE MECHANISM FORTOOL ELE OR THE LIKE Theodor A. OLeary, New York, N.Y., assignor of seven and one halfi'percentito Jordan KunihNew'Ycrir, NH.

Application May 23,1957, erial No. 662,039

12- Claims. (Cl. 145-60) This invention relates. to new and useful" improvements in. mechanical actions for. tool elements or the like. is The present invention is particularly adapted for use in an.

improved" tool for driving a screw havinga special type of slotformedin the head portionthereof.

The present invention also comprises improvements on my previous; invention disclosed in United States Patconsiderably simplified and more eflicient mechanism for.

operating the pair of bits that coact. with. the special typeof: slot in. the head: of the'screw'.

I n-operating. the screw driver, it is desirable-to provide 7 that the-bit. actuating-mechanism maintain: the bits firmly irr their respective open and closed positions. This is accomplished, accordingv to the present invention, by anovel springi controlled toggle mechanism which' exerts itsgreatestiforcein either of the two extreme positions: wherethe bit-s are open; and where the bits are closed.

Additionally the spring? action isarranged to exert'its least force in. theintermediate positions when the bits are passing from the open position to the closed posit-ion;-.and vice versa, so that rapid. and positive engaging: and disengaging? actions.- are effected;

' The new bit actuating'mecha'nism is now completely enclosed: in theshaft? barrel of the driver and is-substa'ntialiy sealed: off. from: dust or. dirt. particles which: might otherwise interfere with: its operation; 'In addition to eliminating multifarious part present in previous screw drivers ofi this type which were subject to various: stills-- tural andoperational failures, the-present: invent-ion also provides. a: virtually foolproof bit actuating mechanism:- which' is considerably less expensive to-manufactnre and.

to" assemble. into the driver.

Still other objects and advantages of my invention: will be: apparent: from the specification;

The features of novelty which I. believe'to' be chast acteristie-Iof my invention are set fortlr herein and will. best beunderstood, both as to their fundamental: prim-- cipl'es and as to their particular embodiments-,- by refer--- ence to the specification and accompanying drawings,v in which: 5

Figure: 1 is an elevation ofi an". embodiment or the screw driver of the present invent-ion together with a screw ada ted to be" engaged thereby;

Fig; 2 is an enlarged view, partly broken away and partly in phantom outline, of theembodiment shown in Fig; I, some ofthe interior parts of the invention being shown in elevation, with the screw engagingbits in the open projecting position; v d

Fig: 3 is a view similar to- Fig. 2, except that some of the interior parts areshown in section which were other-- wise-shown ih elevation Fig; 2:

Fig. 4 is a. central section view, partly in phantom outline, similar to Figs. 2 and 3 withthe screw engagihg. bits shown retracted and closed in engagement with. a

screw;

Fig. 5 is. a View similar to Fig. 4 and illustrates-the spring-toggle mechanism for operating the bits in. an intermediate position; 7

Fig. 6 is a top plan view of. a special type of screwhead used in conjunctionwith the driver of the present invention; 7

Fig. 7 is a partial cross section' view taken along line 7-7 of Fig. 4; I

Fig; 8 is a section. view taken on line 8-8 of Fig. 7;

Fig. 9 is a section view taken on line 9-9 of Fig. 7;,

Fig. 1 0 is a section view taken on line 10-40 of.

Fig. 7; I

Fig; 11: is a partially exploded view, in perspective,

-the-retractedposition', for resetting the bits; and

Fig. 14 is a view similar to Fig. 13. showingisaidre setting means in the forward posit-ion for projecting the bits. i

Referring: to the drawings in detail, the screw driver of the present invention comprises a' solid shank- 21 which may be adapted to be secured: in the chuck of a power.

bit, on the like, although-it is understood that if a hand.

driver is desired, this shank portion may be elongated. and a handle secured to the other: end thereof.. Shank: 2t has a stub 22 formed integrally therewith (Figs-MA and 7 )2, said stub accommodating. the' end of. barrel 23;. of. cylindricalor. other suitable shape; B'arrelI 23" may be secured to-stub 22 by means oiapress fit; swaginge.

or by screws, bolts or the. like;

Stub 22 has: aa peripheral recess 24- which sliadably acc-ommodates theflat'i'shaink 25 of a pusher element having;

- ahand-152 6: the fornr of 'a'. laterally extending bight:

at one end and apusher plate 27 at. the other end exi--- tending into thein'terior'ofi barrel23 (Fig; 44);; The tunetion: of this pusher. element will be described-mores full-Y hereinbelow.

' The forward endtofibarrel'. 23 has aipair of: integrally formed opposed extensions 32 1i which accommodate respective opposed recesses 32 (:Fig; 111) of: a substantially" circular-I bit: supporting plate 33'; Plate 3:3 has: a substantially' centrally located rectangular slot 3* through: which: screw'bits 35: and 36 are adapted to move I'ongi tudinally lni respect ofi barrel 23'. The outer surface of plate- 33 has: a: circular or oval concave recess 37 (Fig.

lb). "adapted to receive" the-upper surface of a screw in the event the latter has a circular or oval convex head. This"; circular recess isof lesser diameter than that of the upper surface of. a1 flat head screw which the driver is adapted: to engage so that t here remains an adequate amountiof flatsurface on the face of'plate 33 to coop era't'e with said screw head whereby firm engagement is maintained during the driving: operation.

It will be noted that the opposed arcuate recesses 32- drive screw; 37.

The Hat head 38' of screw 37 has a slot 39 whose Patented May 1.0, 19.60

concave inner wall ends somewhat short of the periphery of the screw head. The side walls 41 of the screw slot converge inwardly toward the central portion thereof; also, each bit 35 and 36 is provided on both flat sides w th tapered recesses 42 and 43, respectively, which coact'with said slot. When bits 35 and 36 move together said tapered portions enter into opposite ends of slot 39 and engage the, converging Walls of slot 39 to form a substantially dovetail connection therebetween. In this position, as shown particularly in Fig. .4, the screw head 38 is held in firm engagement against the outer face of plate 33 and the shank of screw 37 is held substantially in axial alignment with shaft 21 and barrel 23, whereby a positive driving actionis produced, upon the screw when shaft 21 is rotated.

Plate 33 is provided with a pair of integrally formed rear extensions 45 and 46, the outer surfaces of said extensions being shaped to fit closely with the interior surface of barrel 23. Extensions 45 are spaced *apart from each other to provide a slot within which the respective shanks 47 and 48 of bits 35 and 36 move longitudinally in respect of barrel 23. Extensions 45 and 46 are secured firmly within barrel 23 by means of pin 51 extending through suitable axially aligned apertures in said extensions and in barrel 23. Pin 51 may be provided with a threaded head 52 which engages adjacent threaded apertures in barrel 23 and extension 45 to provide for the ready removal or assembly of plate 33 in respect of barrel 23.

Shank 48 of bit 36 is somewhat shorter than shank 47 of bit 35, both of said juxtaposed shanks being of substantially the same thickness and being angularly slidable relative each other. Shank 48 has an obtuse angled V-shaped slot comprising slot arm 52 and slot arm '53 communicating with each other. Shank 47 also has a comparable obtuse angled V-shaped slot comprising slot arm 54 and slot arm '55 communicating with each other. The V-shaped slot of shank 47 is oriented in a direction opposite that of the V-shaped slot of the shank 48. Pin 51 extends through and is engaged by both of said V- shaped slots when shanks 47 and 48 are caused to move longitudinally in respect thereof.

a The retraction of shank 47 toward the rear of barrel 23 causes the retraction of shank 48 by the action of curved shoulder 58 on shank 47 slidably engaging a complemental curved shoulder 59 on shank 48 (Fig. 7), thereby causing the retraction of bits 35 and 36 at least partially into barrel 23. When bits 35 and 36 are'being retracted into barrel 23 from their previous open positions shown in Figs. 1, 2 and 3, they are urged toward their closed positions as shown in Figs. 4, 5, 7 and 11, by means of the movement of the curved lateral edges of said bits against the end walls of slot 34 in plate 33 as well as by the engagement of the outer ends of said bits with the inner wall 39 of the slot in screw head 38. Bits 35 and 36 are maintained in the closed position by the outer ends of slot arms 52 and 54 bearing against pin 51. In this position slot arms 52 and 54 are substantially in alignment with each other.

The outward movement of shank 47 causes the outward movement of shank 48, by the action of curved shoulder 61 on shank 47 slidably engaging a complemental curved shoulder 62 on shank 48 (Figs. 4 and As shanks and 48 move outwardly from barrel 23, their movements are substantially parallel while slot arms 52 and 54 slidably engage pin 51 until said pin reaches the apex of the respective V-shaped slots in said shanks. Further outward movement of shanks 47 and 48 causes the apices of their respective V-shaped slots to move past pin 51 and to cause slot arms 53 and 54 to engage said pin and produce a scissors action between said shanks thereby causing bits 35 and 36 to protrude from barrel 23 and to separate as shown in Figs. 1, 2 and 3.

The rear end of shank 47 has an aperture 65 which pivotally accommodates a lateral finger 66 on the forward end of control rod 67. Pivotally connected at or near the rear end of rod 67, by means of a common rivet or pin 68 is a pair of short toggle bars 69 and 71.

The outer end of toggle bar 69 is pivotally connected to pin 72 mounted between spaced apart tines 73 of spring blade 74 secured by suitable means to the interior of barrel 23. The outer end of toggle bar 71 is pivotally connected to pin 75 mounted between spaced apart tines 76 of spring blade 77 secured by suitable means to the interior of barrel 23 opposite spring blade 74. Blades 74 and 77 are bent and spring tempered sufi'iciently to cause their outer ends to flex normally toward the axial center of barrel 23 and toward each other.

In one embodiment spring blades 74 and 77 may be provided in the form of a unitary stamping of spring tempered steel as shown in Fig. 12, said blades being integral with a band 78 which is subsequently formed into a ring (Fig. 11), that is secured in position by suitable means on the interior of barrel 23. One method of securing band 78 into a fixed position is accomplished by providing a notch 79 of semi-circular or other suitable shape at the respective ends of band 78, said notches being opposite each other when band 78 is formed into a ring. When positioned opposite each other as shown in Fig. 11, notches 79 are adapted to accommodate the tapered end 81 of set screw 82 passing threadably through a suitable aperture in barrel 23 (Figs. 7 and 9). The tapered end 81 of screw 82 urges the ends of band 78 apart whereby its diameter is expanded and is caused to engage the interior walls of barrel 23 with a tight fit. After being secured in position in this manner, rotational and longitudinal movement or ring band 78 relative tobarrel 23 is effectively prevented.

When open bits 35 and 36 (Figs. 1-3) are urged against slot 39 of screw head 38, said bits simultaneously close toward each other within slot 39 and retract rearwardly into barrel 23, the rear end of shank 47 moving longitudinally and somewhat obliquely further to the rear of barrel 23, as can be seen by the relative positions of said shank in Figs. 3 and 4. The rearward movement of shank 47 also causes the rearward movement of control bar 67 during which time toggle bars 69 and 71 change their position from that shown in Fig. 3 to that shown in Fig. 4.

While bits 35 and 36 are in the open position as shown in Figs. 2 and 3, for example, spring blades 74 and 77 exert their pressure through toggle bars 69 and 71 and control bar 67 to maintain said bits in the open position. The particular combined positions assumed by spring blades 74 and 77 with toggle bars 69 and 71 produce virtual semi-locking action upon bar 67 and, consequently, upon bits 35 and 36. This semi-locking force must be overcome by a predetermined degree of pressure upon bits 35 and 36 to cause them to retract into barrel 23. Once this predetermined pressure is overcome, the rearwardly moving control bar 67 causes toggle bars 69 and 71 to pivot around pins 72 and 75, respectively, against the action of spring blades 74 and 77, until the rearward limit of motion of control bar 67 is reached, where said spring blades have returned to their flexed positions as shown in Fig. 4. In this position, bits 35 and 36 have engaged slot 39 of screw 37 and the tool is ready to drive the screw.

After the driving operation is completed, as shown in Fig. 5, shaft 21 and barrel 23 are pulled longitudinally away from screw 37 causing bits 35 and 36 to move longitudinally out of barrel 23 during the time when pin 51 is engaged by slots 52 and 54 of shanks 47 and 48, respectively. Subsequently, slot arms 53 and 55 of shanks 48 and 47, respectively, pass into engagement with pin 51 and act as cams to cause the bits to move outwardly into their positions shown in Figs. 1 through 3.

At the beginning of the outward movement of shank 21 and barrel 23 to cause the disengagement of the tool from screw 37, resistance to said outward movement is alforded by thecombination of spring blades and 7-7 acting in conjunctionwith toggle bars 69*a'nd 71' in. their position as{ shown in Fig. 4. 7 Here again, there is a semi-locking action produced by said spring; blades and toggle bars upon control bar 67, which must be overcomeby the longitudinal force applied to shank 21' and barrel 23 away from screw 37.

In the intermediate position between either of the semilocking positions shown in Figs. 3 and 4, respectively, and as illustrated in Fig. 5, for example, least resistance is applied by spring'bl'ades 74 and 77 upon the longitudinal motion of control bar 67', whereas thestrongest pressure is applied with increasing force by said spring blades and toggle bars as control'bar 67' approaches-either of its extreme positions shown in Figs. 3 and 4'; Thus, once. the initial resistance of the semi-locking action of the spring blade and toggle combination is overcome, this resistance rapidly diminishes towards the intermediate position as shown in Fig. 5-; and when control bar 67 passes in either direction beyond said intermediate: position, the force exerted by spring blades 74 and 77 irrcreases geometrically to urge control bar 67' againinto the semi-locked position. By this means, bits 35 and 36 are caused either to part rapidly andbecome disengaged readily from slot 39'of screw" 37 when the tool is pulled away from screw 37,. or to close together rapidly and firmly toengage said slot when the tool is urged against the head of the screw.

From the foregoing it can be understood that the characteristicaction of the spring blade, toggle bar combination described herein is. opposite that. of the conventional spring-toggle action wherein the least resistance is manifest at each extreme of the toggle strokes, and is greatest at the intermediate positions of said strokes By providing. the strongest forces at theextreme ends: of the toggle strokes herein, and the least force at the" intermediate! positions, I provide for more. positive action. for bits 35 and 36 to approach and to assume their extreme open or closed positions, which enhances the effectiveness of the screw driver described herein.

The dimensions of toggle bars 69 and 71, and of spring blades 74 and 77, as well as the extent of fiexion of said spring blades, may be predetermined to provide the most desirable degree of the semi-locking action described herein.

Although the spring-toggle bar action disclosed and described herein is one preferred embodiment of the invention, other comparable mechanisms are contemplated for producing this special type of action which would also provide a semi-locking action at the extreme ends of the alternating mechanism as well as produce increasing forces as the mechanism approaches either of its extreme positions.

Occasionally, when bits 35 and 36 become retracted, as shown in Figs. 7 and 11, for example, it is necessary to cause their protrusion from barrel 23, as shown in Figs. l through 3 in order to permit the tool to engage a screw. Thumb pressure applied forwardly upon handle 26 will cause pusher plate 27 to be urged against the rear end of control rod 67 and to cause the forward movement of the latter and the consequent movement of bits 35 and 36 to the open position as shown in Figs. 1 through 3. After this is accomplished, the pusher handle 26 is retracted manually to its original position so that the toggle mechanisms within barrel 23 are free to operate as described hereinabove.

Although in some embodiments pusher plate 27 may be arranged substantially perpendicular to shank 35, it is illustrated as being positioned at an oblique angle relative thereto in order to assist the pivotal motion of control bar 67, as it changes from its position shown in Fig. 4 to that shown in Fig. 3.

Handle 26 is convenient to operate by thumb pressure in connection with manually operated screw drivers. If, however, the driver is to be power driven by a hand held 5 electric motor or the like, the rapid rotation of laterally extending handle 26 around shaft 21 may prove hazard-- ous. Consequently, I provide alternative means for manipulating pusher plate 27', as illustrated in- Figs: 13- and 14. Mounted around barrel 23 is a knurled ring 91- to the rear edge of which is attached; by' suitable means such as welding, brazing, or"the like, a laterally extending arm 92' connected to or integral with: therear. end of shank 25. tudinally over barrel 23 and in. Fig. 13 it: is: shown in the retracted position. IrrFig. 14 it is shown in. the for ward position for causing the projection of bits 35 and 36. It is. apparent that. upon rapid? rotation. of the driver; the circular knurled ring; 9 1'fminirn'izes thehazards to i which the operator is subjected in handling: the to'olr When-the tool of the present invention is to be used with motor driven devices, the rear end of shank 21 provided with a tang or plug 93- for securing, the tool in:

asuitable chuck.

It is apparent that the spring-toggle mechanism for the control. rod in the screw' driver described. herein. may also be adapted for use in other types of tools; electric switches,.or other types of. apparatus where semi-locking: actions are desired at the extreme positions of'a reciproeating element and where comparatively less resistance is imposedupon the motion of said element. during its:

my invention from other inventions; and I have particularly' pointed out and distinctly claimed" the part, mode or combination which I claim: asmy invention: or. dis-- covery.

While I have shown and: d'escribedcertain preferred embodiments of my invention, itwill. be understood that. modifications and changes may be made without departing. from the function and scope thereof, as will be clear to those skilled in the art.

I claim:

1. A screw driver comprising a barrel, a pair of bits jointly movable at least partially into and out of the interior of said barrel between two extreme positions, a control bar connected to said bits and movable longitudinally within the interior of said barrel, a pair of spring blades, one end of each of said spring blades being connected to opposite lateral locations on the interior of said barrel and being disposed longitudinally thereof, said spring blades being biased to cause their other ends normally to flex toward said control bar, and a pair of toggle bars, one end of each of said toggle bars being connected pivotally to respective flexed ends of said spring blades, the other ends of said toggle bars being connected to a common pivot point on said control bar.

2. A driver according to claim 1, and further comprising a metal band formed into substantially circular shape and secured firmly in position on the interior of said barrel, said spring blades being formed integrally with said band.

3. A driver according to claim 2, and further comprising a notch at each end of said band, a screw threadably passing through the wall of said barrel and engaging both of said notches simultaneously to cause the ends of said band to be urged apart whereby said band is caused frictionally to engage the interior walls of said barrel.

4. A driver according to claim 1, and further comprising a shank movable longitudinally .in and out of said barrel, one end of said shank being adapted to engage an end of said control bar to cause the latter to move against the action of said spring blades. 1.

5. A driver accordingto claim 4 wherein said control bar moves pivotally as well as longitudinally relative to the axis of said barrel, and further comprising a lateral projection on said shank within the interior of said barrel, said projection being disposed at an angle relative to said Ring 91' is manually movable longi-' axis whereby it assists the pivotal action of the control bar when the latter is engaged thereby.

6. A driver according to claim 5, and further comprising a projection on said shank positioned externally of said barrel for manual operation of said shank.

7. A positioning system for the components of a tool comprising a barrel, a control rod movable longitudinally within said barrel, a pair of spring blades, said blades being disposed substantially longitudinally of said barrel, one end of each of said spring blades being connected to opposite positions on the interior of said barrel, each spring blade being biased to cause another end thereof normally to flex toward said control bar, a pair of toggle bars, one end of each of said toggle bars being connected pivotally to a flexed end of a respective spring blade, the other ends of said toggle bars being connected to a common pivot point on said control bar, said springblades normally urging said toggle bars to assume an angle between them when said control bar is in either one of two extreme positions.

8. A system according to claim 7 wherein said toggle bars assume an acute angle between them when said control bar is in either one of two extreme positions.

9. A system according to claim 7, and further compris ing a metal band formed into substantially circular shape and secured firmly in position on the interior of said barrel, said spring blades being formed integrally with said band.

10. A system according to claim 9, and further comprising a pivot pin connection between each toggle bar and its respective spring blade, said connection being urged against a respective side of said control bar when the latter is in either one of two extreme positions.

11. A mechanical action comprising a frame, an element movable longitudinally within said frame, a pair of spring blades, said spring blades being attached to opposite respective portions of and extending longitudinally of said frame, a pair of'tines on each spring blade, said pairs of tines being spring biased toward said element, a pivot pin supported by each pair of tines, a toggle bar pivotally connected at one end to each pivot pin between said tines, the other ends of said toggle bars being connected pivotally to said element, said pairs of tines jointly urging said toggle bars normally into either of two opposite angular positions relative to each other to cause said element to assume either of two corresponding semilocked positions, the angles between said toggle bars being limited by the respective lateral edges of said element.

12. A mechanical action comprising a barrel, an element movable longitudinally in the interior of said barrel, a metallic strip formed into a ring and positionedon the interior of said barrel around said element, a notch in each end of said strip, said notches being positioned opposite each other when said strip is formed into a ring, a threaded pin extending through the wall of saidbarrel and adapted to engage said notches to urge the ends of said strip apart to cause the latter firmly to engage the interior walls of said barrel, a pair of spring blades integral with said strip and extending from respective opposite sides of said barrel and being biased toward said element, and a pair of toggle bars, one end of each of said toggle bars being connected pivotally to the biased portion of a respective spring blade, the other ends of said toggle bars being connected to a common pivot point on said element.

References Cited in the file of this patent UNITED STATES PATENTS 905,426 Haywood Dec. 1, 1908 2,304,703 OLeary Dec. 8, 1942 2,671,632 Palmer Mar. 9, 1954 2,748,214 Immel May 29, 1956 2,782,277 Immel Feb. 19, 1957 

